net: Move CONFIG_E1000 options to Kconfig

Move config for the E1000 Ethernet driver to Kconfig and tidy up affected
boards.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/configs/ls1021atwr_qspi_defconfig b/configs/ls1021atwr_qspi_defconfig
index 6c35918..4e5f100 100644
--- a/configs/ls1021atwr_qspi_defconfig
+++ b/configs/ls1021atwr_qspi_defconfig
@@ -7,4 +7,6 @@
 CONFIG_OF_CONTROL=y
 CONFIG_DM=y
 CONFIG_SPI_FLASH=y
+CONFIG_NETDEVICES=y
+CONFIG_E1000=y
 CONFIG_DM_SPI=y